High sensitive protein fluorescence sensing on nano ring gap (NRG) LSPR sensor

This paper proposes a novel nanosensing platform for protein fluorescence enhancement by nano ring gap (NRG) induced Localized Surface Plasma Resonance (LSPR). On this platform, gold nanoparticles (GNPs) surrounded by silver sheathes with a nanosized gap were designed and successfully fabricated for protein immobilization/detection. Through simulation, when the nano ring gap between silver sheath and gold nanoparticle reduced to 15 nm, the light intensity can be enhanced by around 8.5 folds of magnitude than that of the 5 nm gap sensor. Experiment result has also verified the fluorescence enhancement by 7 fold for bound protein on GNPs. This platform will be further tailored for single protein molecule detection in the future.